@labiker9: We Are One is the real deal, but Tairin uses Yishun rims. They claim to [i]lace[/i] the wheels in house, but they're just reselling products you can buy directly from Yishun for less. That said, Yishun rims are among the nicest rims on the market, so I'm not saying it's a bad product.

I would propose:
1: Maximum of three sets of standards for disc hubs, BBs, etc., being road, dirt, and fat. There will be crossover, with XC racing bikes using road parts and road tandems using dirt parts, but let's keep it to three. And let's try to skip ahead a generation, while we're at it.
2. Hubs or axles that can handle torque, such as the SRAM Torque Cap or Manitou's Hex Lock.
3. Offset frames and forks for better symmetry of spoke bracing angles. Offset them by the width allocated to the rotor.
4. Simplify disc caliper spacers by using only "+10 mm", "+20 mm", etc.
5. Freebodies that make use of the space inside cassettes, such as the Kappius design. Perhaps a road standard that would accept a minimum 25 T sprocket (does anyone still use an 11-23 cassette?) and a dirt standard that would have a minimum 40 T.
6. Integrated dropper posts. Something along the lines of the Eightpins and KS Genesys designs is the way forward, but will only be adopted if we can agree on a diameter and mounting standard.
I'll take a guess at some standards we could live with for several years. They're burlier than the current norms and seem like overkill, but things always go that direction, so let's extrapolate beyond current needs:
Front hub:
- Road: 110 x 15 mm (current Boost).
- Dirt: 120 x 25 mm. It's conceivable this could be spaced down to the road/XC race standard with end caps.
- Fat: I don't know what you people need. Maybe 180 mm x 25 mm?
Rear hub:
- Road: 142 x 12 mm with maximum flange spacing.
- Dirt: 157 x 15 mm. Super Boost with a slightly larger axle. Or maybe wider, if we decide to put the outermost bearing on the drive side outboard of the cassette.
- Fat: How about 180 x 25 again to keep things simple?
BB:
Pressed-in bearings can work, but threaded systems have been a lot easier to live with, are easier to manufacture, and frame designers can still maximize pivot spacing.
Chainline:
Centre it on the cassette. Current chainlines are offset to the outside for added tire clearnace, which is why we can’t backpedal in the largest sprocket. With offset frames, we can maintain tire clearance and improve chainline.

@TheRaven: Cheers on the civil discussion! My take is that SLX is below GX-12 on only two counts: the shifter and the cassette range. The shifter is crude and the range isn't on par with GX-12. I would put an XT group with SLX cranks on par with GX - and I'd run a tiny ring to compensate for the reduced range.
"Value" is difficult to quantify. If you want the best component spec for your money, there are some direct sale, catalog frames that offer outstanding specs at reasonable prices. I would argue the aluminum Pivot or Santa Cruz frames being discussed are much nicer, though, and I'd rather have a posh frame with budget parts than vice versa.
If a person can find a cheap bike with great geometry, though, that's the best of both worlds! Whyte and Bird are particularly good examples, in my opinion.

Personally, I favour the 54 mm jump in normalized reach (factoring in the effect of stack) between sizes, as I feel most product lines don't cover enough range on the long end, but yeah, whether you like long or short bikes, the unevenness of these sizes is unusual.

@coregrind: I also find the recommended pressure too high. The problem could be due to the travel setting: note how the recommended pressures on the chart decrease with increasing travel. If your Ribbon is set up for 170 mm, I recommend going down another pressure increment, compared to the other travel recommendations. This works out to about 13% lower than the pressures recommended for 150 mm travel.

I would guess the extra power of the Trail brakes allows him to use a smaller rotor size, which saves more weight - unsprung, at that - than is gained by the Trail levers. Or maybe he's committed to the lighter 160 mm rotors and this just provides a little more power.